<template>
  <div class="app-container">
    <!--查询表单-->
    <el-form :inline="true" class="demo-form-inline">
      <!-- 所属分类：级联下拉列表 -->
      <!-- 一级分类 -->
      <el-form-item>
        <el-select
          v-model="searchObj.subjectParentId"
          placeholder="请选择课程类别"
          @change="subjectLevelOneChanged"
          clearable
        >
          <el-option
            v-for="subject in subjectList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"
          />
        </el-select>

        <!-- 二级分类 -->
        <el-select v-model="searchObj.subjectId" placeholder="请选择" clearable>
          <el-option
            v-for="subject in subjectLevelTwoList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"
          />
        </el-select>
      </el-form-item>

      <!-- 标题 -->
      <el-form-item>
        <el-input v-model="searchObj.title" placeholder="课程标题" clearable />
      </el-form-item>

      <!-- 讲师 -->
      <el-form-item>
        <el-select
          v-model="searchObj.teacherId"
          placeholder="请选择讲师"
          clearable
        >
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"
          />
        </el-select>
      </el-form-item>

      <!-- 课程状态 -->
      <el-form-item>
        <el-select v-model="searchObj.status" clearable placeholder="课程状态">
          <el-option :value="'Normal'" label="已发布" />
          <el-option :value="'Draft'" label="未发布" />
        </el-select>
      </el-form-item>

      <el-button type="primary" icon="el-icon-search" @click="fetchData()" plain
        >查询</el-button
      >
      <el-button type="default" @click="resetData()">清空</el-button>
    </el-form>

    <el-table :data="list" border stripe>
      <el-table-column label="ID" width="50">
        <template slot-scope="scope">
          {{ (page - 1) * limit + scope.$index + 1 }}
        </template>
      </el-table-column>

      <el-table-column label="封面" width="200" align="center">
        <template slot-scope="scope">
          <img :src="scope.row.cover" alt="scope.row.title" width="100%" />
        </template>
      </el-table-column>
      <el-table-column label="课程信息">
        <template slot-scope="scope">
          <a href="javascript:void(0)">{{ scope.row.title }}</a>
          <p>
            分类：{{ scope.row.subjectParentTitle }} >
            {{ scope.row.subjectTitle }}
          </p>
          <p>
            课时：{{ scope.row.lessonNum }} / 浏览：{{ scope.row.viewCount }} /
            付费学员：{{ scope.row.buyCount }}
          </p>
        </template>
      </el-table-column>
      <el-table-column label="讲师" width="100" align="center">
        <template slot-scope="scope">
          {{ scope.row.teacherName }}
        </template>
      </el-table-column>
      <el-table-column label="价格(元)" width="100" align="center">
        <template slot-scope="scope">
          <el-tag v-if="Number(scope.row.price) === 0" type="success"
            >免费</el-tag
          >

          <!-- 前端解决保留两位小数的问题 -->
          <!-- <el-tag v-else>{{ Number(scope.row.price).toFixed(2) }}</el-tag> -->
          <el-tag v-else>{{ scope.row.price }}</el-tag>
        </template>
      </el-table-column>
      <el-table-column
        prop="status"
        label="课程状态"
        width="100"
        align="center"
      >
        <template slot-scope="scope">
          <el-tag
            :type="scope.row.status === 'Draft' ? 'warning' : 'success'"
            >{{ scope.row.status === "Draft" ? "未发布" : "已发布" }}</el-tag
          >
        </template>
      </el-table-column>
      <el-table-column label="创建时间" width="120" align="center">
        <template slot-scope="scope">
          {{ scope.row.gmtCreate.substr(0, 10) }}
        </template>
      </el-table-column>

      <el-table-column label="操作" width="300" align="center">
        <template slot-scope="scope">
          <router-link :to="'/course/info/' + scope.row.id">
            <el-button type="primary" size="mini" icon="el-icon-edit"
              >修改信息</el-button
            >
          </router-link>
          <router-link :to="'/course/chapter/' + scope.row.id">
            <el-button type="primary" size="mini" icon="el-icon-edit"
              >编辑大纲</el-button
            >
          </router-link>
          <el-button
            type="danger"
            size="mini"
            icon="el-icon-delete"
            @click="removeById(scope.row.id)"
            >删除</el-button
          >
        </template>
      </el-table-column>
    </el-table>

    <!-- 分页组件 -->
    <el-pagination
      :current-page="page"
      :total="total"
      :page-size="limit"
      :page-sizes="[5, 10, 20, 50, 100]"
      style="padding: 30px 0; text-align: center"
      layout="total, sizes, prev, pager, next, jumper"
      @size-change="changePageSize"
      @current-change="changeCurrentPage"
    />
  </div>
</template>

<script>
import { getPageList, removeCourseById } from "@/api/course";
import { getList } from "@/api/teacher";
import { getSubjectList } from "@/api/subject";

export default {
  data() {
    return {
      list: [],
      total: 0,
      page: 1,
      limit: 10,
      searchObj: {
        subjectId: "",
      },
      teacherList: [],
      subjectList: [],
      subjectLevelTwoList: [],
    };
  },
  created() {
    this.fetchData();
    this.initSubjectList();
    this.initTeacherList();
  },
  methods: {
    //显示课程列表
    fetchData() {
      getPageList(this.page, this.limit, this.searchObj).then((res) => {
        this.list = res.data.records;
        this.total = res.data.total;
      });
    },
    initTeacherList() {
      getList().then((res) => {
        this.teacherList = res.data;
      });
    },
    initSubjectList() {
      getSubjectList().then((res) => {
        this.subjectList = res.data;
      });
    },
    //下拉列表联动
    subjectLevelOneChanged(value) {
      this.subjectList.forEach((subject) => {
        if (subject.id === value) {
          this.subjectLevelTwoList = subject.children;
          this.searchObj.subjectId = "";
        }
      });
    },
    //重置表单
    resetData() {
      this.searchObj = { subjectId: "" }; //清空查询条件
      this.subjectLevelTwoList = []; //二级分类列表
      this.fetchData(); //重新查询
    },
    //每页记录数改变，size：回调参数，表示当前选中的“每页条数”
    changePageSize(size) {
      this.limit = size;
      this.fetchData();
    },
    //改变页码，page：回调参数，表示当前选中的“页码”
    changeCurrentPage(page) {
      this.page = page;
      this.fetchData();
    },
    //删除课程
    removeById(id) {
      this.$confirm(
        "此操作将永久删除该课程，包括所有的章节与视频，是否继续?",
        "提示",
        {
          confirmButtonText: "确定",
          cancelButtonText: "取消",
          type: "warning",
        }
      )
        .then(() => {
          return removeCourseById(id);
        })
        .then((response) => {
          this.fetchData();
          this.$message.success(response.message);
        })
        .catch((response) => {
          if (response === "cancel") {
            this.$message.info("已取消删除");
          }
        });
    },
  },
};
</script>

<style>
</style>